The beginning student of music is typically overwhelmed at the outset of his study by the extensive permutations which arise from the number of distinct musical scales and the various rules applicable to the identification of chords and the like. By way of example, he is required to correlate single notes of the 12-step chromatic scale notes with the various scales of lesser and varying step content in appreciating melodic composition. This relatively simple correlation endeavor is expanded greatly in his efforts to understand harmonic composition, i.e., correlation of counterpart chords in respective different scales. Indeed, it is the exceptional skilled musician who can master the involved permutations without resort to reference materials.
The art has long recognized the problem at hand and has evolved various so-called musical slide rules, calculators and the like intended to facilitate solving the correlation problems. Such musical slide rules and calculators as are known to applicant include those shown in U.S. Pat. Nos. 1,643,303, 3,592,099, 3,728,932, 2,657,610, 3,635,122, 3,481,241 and 675,345.
Certain of these patents disclose devices which are encyclopedic in character, containing musical indicia in quite extended quantity. Typically, they present solutions together with a visually distracting excess of information. Others, such as U.S. Pat. No. 1,643,303, disclose devices which are less comprehensive in indicia content and present solutions by displaying only relevant indicia, however, through invariant display regimens of number limited by structural constraints. Thus, in this U.S. Pat. No. 1,643,303, three selectively-apertured rotatable disc members are stacked above a base member which includes indicia defining the steps of the chromatic scale, and this assembly is supported within a casing defining fixed further apertures. The student sets up a problem by preselected manipulation of the multiple disc members of these devices and the device selectively displays no more indicia than are involved in the solution. Thus, while preferable to the non-selective presentation devices of the other prior art patents, this type of device has structural complexity and problem solving limitations.
Absent from such heretofore known arrangements of musical calculators are characteristics of adaptiveness to student experimentation and effective integration of the display device and supplemental knowledge which the student generally has. The prior devices are thus considered traditional in direction, not permitting a student to pursue examination of musical arrays beyond the conventional and limiting his participation in the problem solving experience.